.. _rvarplt:
RangeVarPlot
------------
.. class:: RangeVarPlot
Syntax:
``RangeVarPlot("rangevar")``
``RangeVarPlot("expression involving $1")``
Description:
Class for making a space plot. eg. voltage as function of path between
two points on a cell. For plotting, an object of this type needs
to be inserted in a Graph with
\ ``g.addobject(rvp)``
By default, the location of the path nearest the root is location 0
(the origin) of the space plot.
If the *rangevar* does not exist at certain places in the path it
is assumed to have a value of 0.
The first form where *rangevar* is "*v*" or "*m_hh*", etc. is very
efficient since the object can store pointers to the variables
for fast plotting.
The second form is much slower since the expression
must be executed by the interpreter for each point along the path
for each plot. Execution of the expression is equivalent to
\ ``forsec seclist`` for (*x*) f(*x*)
where the expression is the body of f. (Hence the use of $1 to
denote the arc length position of the (temporary
currently accessed section.)
.. seealso::
:func:`distance`, :meth:`Graph.addobject`
Example:
An example is plotting the transfer impedance with
.. code-block::
none
objectvar imp, rvp, g
imp = new Impedance()
rvp = new RangeVarPlot("imp.transfer($1)")
rvp... //specify range begin and end
imp... //specify impedance computation
g = new Graph()
g.addobject(rvp)
----
.. method:: RangeVarPlot.begin
Syntax:
``.begin(x)``
Description:
x position of the currently accessed section that starts the
path used for the space plot.
----
.. method:: RangeVarPlot.end
Syntax:
``.end(x)``
Description:
x position of the currently accessed section that ends the
path used for the space plot.
----
.. method:: RangeVarPlot.origin
Syntax:
``.origin(x)``
Description:
x position of the currently accessed section that is treated
as the origin (location 0) of the space plot. The default is usually
suitable unless you want to have several rangvarplots in one graph
in which case this function is used to arrange all the plots relative
to each other.
----
.. method:: RangeVarPlot.left
Syntax:
``.left()``
Description:
returns the coordinate of the beginning of the path.
----
.. method:: RangeVarPlot.right
Syntax:
``.right()``
Description:
returns the coordinate of the end of the path. The total length
of the path is ``right() - left()``.
----
.. method:: RangeVarPlot.list
Syntax:
``.list(sectionlist)``
Description:
append the path of sections to the :class:`SectionList` object argument.
----
.. method:: RangeVarPlot.color
Syntax:
``.color(index)``
Description:
Change the color property. To see the change on an already plotted
RangeVarPlot in a Graph, the Graph should be :meth:`~Graph.flush`\ ed.
----
.. method:: RangeVarPlot.to_vector
Syntax:
``rvp.to_vector(yvec)``
``rvp.to_vector(yvec, xvec)``
Description:
Copy the range variable values to the :func:`Vector` yvec. yvec is resized
to the number of range points. If the second arg is present then
the locations are copied to xvec. A plot of \ ``yvec.line(g, xvec)`` would
be identical to a plot using \ ``g.addobject(rvp)``.
.. seealso::
:meth:`Graph.addobject`
----
.. method:: RangeVarPlot.from_vector
Syntax:
``rvp.from_vector(yvec)``
Description:
Copy the values in yvec to the range variables along the rvp path.
The size of the vector must be consistent with rvp.